The acquired immunodeficiency syndrome (AIDS) has become a global pandemic, with cases reported in 138 countries throughout the world. An intensive research effort has been undertaken in several countries in the Caribbean and Africa to study the unique epidemiologic, virologic, clinical, an immunologic features of AIDS in these areas. In Kinshasa, Zaire, we identified over 10,000 cases of AIDS in 1987 with a male to female ration of 1:1.5. The disease is predominantly heterosexually transmitted with high seroprevalence rates to the human immunodeficiency virus (HIV) of 3-6% among the general heterosexual population in Kinshasa in contrast to <1% in rural Africa. HIV infection rates of 20-80% have been documented among spouses of AIDS patients, female prostitutes, and among patients attending STD clinics. Similar studies in the U.S. have confirmed a 5% infection rate among patients attending STD clinics with increasing evidence of heterosexual transmission among these patients. The presence f genital ulcerations were significantly associated with heterosexual transmission. In studies of perinatal transmission of HIV infection, over 15,000 pregnant women in Haiti, Kenya, and Zaire, of whom approximately 6% are HIV seropositive have been enrolled in prospective studies. Perinatal transmission which occurs in approximately 50% of children appears to correlate with advanced clinical disease and immunologic impairment of the mother with depressed T4 cells. Perinatal HIV was associated with premature birth, low birth weight, and an increased mortality (22%) within the first year of life. Childhood immunization studies on HIV infected children demonstrated efficacy of most vaccines with few adverse effects, documenting the continual need form complete immunization programs. Immunologic studies have confirmed the development of HIV-1 specific antibody dependent cellular cytotoxicity (ADCC) in HIV infected African patients which correlated strongly with the development of antibody to gp41. Further studies will continue to examine the frequency of human retroviral infection (HIV-1, HIV-2, HTLV-1) in selected populations with particular emphasis on natural history, perinatal transmission, and immunopathognesis which might have relevance to future vaccine studies.